This invention relates to improvements on a film takeup device for an endoscope having a camera received in a distal end portion of an endoscope sheath.
Recently, an endoscope has been developed which has a camera received in a distal end portion of an endoscope sheath and a film loaded in the distal end portion, thereby photographing the interior of a coelom or body cavity of human or other living beings. A film takeup device for this type of endoscope generally comprises a takeup mechanism including a pulley provided in an operation section of the endoscope, and an operating wire connected to a leading end of a film loaded in a distal end portion of an endoscope sheath or wound about a pulley provided on a takeup shaft of a film cassette. With the above-mentioned arrangement, a rolled film is fed one frame after another, each time the takeup mechanism is operated. Before a rolled film or a film cassette is loaded in the distal end portion of the endoscope sheath, the operating wire is unwound from the takeup mechanism, causing the leading end of the operating wire to be pushed into a film chamber or film cassette chamber, and then the leading end of the film or a film takeup wire wound about the pulley provided on the takeup shaft of the film cassette is connected to the engagement portion of the leading end of the operating wire. Therefore, the longer the leading end portion of the operating wire extended into the above-mentioned chamber, the easier the connection between the operating wire and the film or the film takeup wire.
Where, however, the leading end of the operating wire is extended too much into the aforesaid chamber, the tip of the leading end portion of the operating wire strikes against the inner wall of a cap which closes the tip of the distal end portion of the endoscope sheath, with the possibility of the leading end portion of the operating wire being bent or broken. For this reason, the extent to which the leading end portion of the operating wire is carried into the aforesaid chamber is so restricted that the tip of the leading end portion is prevented from contacting the inner wall of the cap. Therefore, connection between the operating wire and the film or the film takeup wire has presented considerable difficulties, consuming a great deal of time. Moreover, since this connecting work is generally undertaken in a semi-dark chamber, it is not easy to judge whether the connection has been effected reliably, unavoidably leading to an error in the connection.
For resolution of the above-mentioned problems, it may be contemplated to elongate the cap. However, this arrangement is not available for practical application because of the drawbacks that the rigid distal end portion of the endoscope sheath has to be extended, not only presenting difficulties in inserting the distal end portion into the body cavity of human beings, but also causing a patient to feel great pain at the time of the insertion.